Sound navigation and ranging, also known as sonar, is an electronic device that uses the propagation characteristics of sound waves under water to complete underwater detection and communication tasks through electroacoustic conversion and information processing.

It is available in two types, active and passive, and belongs to the category of acoustic positioning. Sonar is an electronic device that uses underwater sound waves to detect, locate, and communicate underwater targets.

The tail end of the submarine is also the part of the power output, and due to the interference of the sound of the water current, the sonar located in front cannot hear the signal in this area, forming a blind spot. By using towed sonar, you will be able to eliminate this blind spot and find the target hiding in this area.

However, at present, the Anonymous-class submarine does not have such an advanced thing as towing sonar at all, so the No. 2 submarine is completely unaware of the Crime submarine that is tracking in the rear.

At this moment, in front of the second submarine, the only safe entrance to the trench is already close at hand.

On the navigation map, the navigator is mapping the distance on the navigation map, and in front of him, there is an electronic second reader, as well as a computer system.

This is the only means by which the submarine can pass through the trench, and that is to calculate the speed of the submarine according to the length of each safe passage section, calculate the time it will travel, and display it in the countdown, and then turn around.

"After a minute, the submarine made the first turn and entered the first channel, and after the first turn into the channel, the speed was eighteen knots, and after three minutes, it turned right, entered the second channel, and sailed ......"

The navigator quickly calculated the current position of the submarine and the time it was from the target channel.

Ling Han and the co-captain were standing on the side, not interfering with the navigator's calculations, and the pilot was also preparing to make a turn.

"Submarine parking." When the navigator calculated the navigation time of the channel, Ling Han suddenly gave the order for the submarine to stop.

Almost everyone in the command looked at their captain, and the deputy commander quickly repeated the command, and the operator stopped the submarine from moving on, the propeller speed slowly stopped, and the advancing submarine also hovered.

In the next second, the sonar officer exclaimed: "If you find the sonar signal of the enemy submarine, damn it, it is 1,500 meters behind us." ”

Ling Han's face was repeated, if this order was just a whim, then it was really a big deal.

An order for the sake of prudence, but it turned out that there was really an enemy behind him, Ling Han ordered without hesitation: "Advance, enter the trench." ”

At the same time, on the Crime, when the sonar officer reported that the other submarine was parking, the captain was obviously stunned for a moment, and the next second his face became hideous, and he roared: "Damn bugs, it will actually stop at this time, the No. 1 torpedo compartment, open it immediately, the torpedo locks, attack." ”

The submarine in front of it, just parked like this, was absolutely unexpected, in fact, this was the most common thing that American and Russian submarines did during the Cold War.

Submarines on both sides are entangled in the ocean. You follow me, I follow you, so you will often stop to see if there is a tail behind you.

In front of the Crime submarine, the No. 1 torpedo hatch opened quickly, and the sound of the hatch opening quickly spread, and the torpedo prepared inside also opened the guidance, locking the No. 2 submarine in front, and the random torpedo was fired.

On the No. 2 submarine, the sonar sirens also sounded one after another: "The opponent's torpedo hatch opened, the torpedo active sonar locked on us, and the torpedo was launched at a distance of 1,500 meters. ”

"Hurry forward, enter the trench right now." Ling Han also almost roared.

Every sailor in the submarine also got busy quickly, and the speed of the submarine suddenly increased, and the submarine rushed into the trench one by one, and the torpedoes in the rear quickly caught up.

An alarm signal sounding inside the submarine that was locked by a torpedo, and red lights flashed inside the submarine.

At the same time as the submarine turned into the trench, Ling Han immediately grabbed the communicator connected to the power compartment and asked, "Wheel chief, can the power system operate at 115%?" ”

The captain quickly replied, "Captain, the power system can run to 115%, but it is not recommended to do that. ”

"Then run 115% and go fast." After Ling Han gave the order, he immediately ordered the navigator on the side: "Recalculate the time." ”

"Captain, it's too fast, we'll be too late to turn." The navigator shouted nervously, this is like a flying car, the next turn is a curve of nearly ninety degrees, the submarine is so fast, it is very likely to hit the submarine mountain.

And a submarine of less than 2,000 tons like Anonymous, once it hits the undersea mountain range, it is still at the limit speed, the ending will be quite tragic.

"Execute the order."

There is an absolutely insurmountable rule on submarines, that is, the captain's order must be fully obeyed, even if it is a head-on collision with the enemy's torpedo.

An order that can change the fate of a war is often thought of and executed in a split second.

When Ling Han's words came out again, the navigator didn't have a second word, and began to recalculate the course, and the overloaded submarine power system had reached a rapid speed of twenty-eight knots at this moment, which was three knots higher than the normal speed of twenty-five knots.

And after this voyage, if the submarine wants to sail again, the power system must be well maintained, and even if it lasts for a long time, the power system may be scrapped directly.

The torpedo that followed closely behind him also crossed an arc on the bottom of the sea, turned into the trench, and continued to chase towards the second submarine.

On the recalculated course, the calculator had fifty-five seconds left in the countdown, and the torpedo approached less than sixty-five seconds.

This made everyone in the command center nervous, and almost all eyes were focused on Ling Han's body.

Ling Han, on the other hand, sat very calmly on the captain's seat, and fixed himself to the captain's command seat with a seat belt, and there was a small table next to him with a cup of steaming green tea.

"Forty seconds left until the torpedo hit." The co-captain looked at the stopwatch in his hand and said.

Hearing this, Ling Han showed a hint of an inexplicable smile and said to his deputy captain: "My teacher, commander, once said a word to us, do you know what it is?" ”

When the deputy captain heard this, he was a little stunned, but his good quality made him not in a daze, but shook his head, saying that he didn't know.

Ling Han said: "As a submarine commander, your orders determine the life and death of everyone, but no matter what, you must trust your own judgment and trust every order you give. ”